Fix flake8 issue where rules are not being observed

1 job for master in 16 seconds (queued for 1 second)
Name Stage Failure
failed
lint Lint
 * [new tag]         1.0        -> 1.0
Checking out 1f55bfdd as master...

Skipping Git submodules setup
$ python3 -m pip install -q flake8
$ cd ./src
$ flake8 ./src
./src:0:1: E902 FileNotFoundError: [Errno 2] No such file or directory: './src'
ERROR: Job failed: exit code 1